Covered Plastic Lock

ABSTRACT

The invention relates to a cover for a surface drainage device or similar hollow body that is to be embedded in the ground and to be opened. The cover comprises an upper surface over which pedestrian and/or vehicular traffic can pass, and at least one locking element that is attached to an underside of the cover such that the upper side is closed over the locking element. The locking element is disposed at a specified distance from the underside in such a way as to form an air gap for thermal insulation between the underside and the locking element.

The invention relates to a cover for a surface drainage device or similar hollow body that is to be embedded in the ground and to be opened, with an upper surface over which pedestrian and/or vehicular traffic can pass, having at least one locking element that is attached to an underside of the cover.

Such surface drainage devices or similar hollow bodies that are to be embedded in the ground and to be opened are employed, for example, in traffic areas, where they serve to remove rain and other water that falls onto the surface of the area. Preferably in this case the cover is set into a frame, casing or similar seating arrangement in such a way that it is flush with the adjacent traffic surface. These covers are customarily such that vehicular but also pedestrian traffic can pass over them.

A problem often encountered with such covers is that because of the stresses associated with the traffic technology, they must be fixedly connected to the substrate so that they cannot be detached even under impulse-like impacts, such as are caused by vehicles travelling over the cover. On the other hand, the covers must nevertheless be opened at regular intervals so that, for example, cleaning and maintenance work can be undertaken.

For this reason they usually comprise locking elements that enable releasable locking to a frame or similar seating arrangements in the substrate. These locking elements are frequently made of plastic materials, because this allows a flexible locking to be produced and furthermore is very economical.

For instance, covers are known in practice in which the associated locking elements are constructed as flexible hook elements and are attached to an underside of the cover. After the cover has been set into a frame or similar seating arrangement, these flexible locking elements become engaged with catches or similar projections and lock the cover in position with respect to the substrate.

It has been shown that locking elements consisting of plastic develop weaknesses, sometimes only shortly after installation and sometimes after rather longer periods of use.

The objective of the present invention is thus to develop a cover for a surface drainage device or similar hollow body that is to be embedded in the ground and to be opened, of the kind cited at the outset, further in such a way as to ensure improved durability of the locking elements.

This objective is achieved by a cover according to Claim 1.

The objective is insofar achieved by a cover for a surface drainage device or similar hollow body that is to be embedded in the ground and to be opened, with an upper surface over which pedestrian and/or vehicular traffic can pass, that has at least one locking element attached to an underside of the cover, such that the upper side is closed above the locking element and the locking element is disposed at a specified distance from the underside so that an air gap is formed between the underside and the locking element, for the purpose of thermal insulation.

A substantial point of the invention thus resides in the fact that the locking element is disposed at a particular distance from the underside of the cover. Customarily covers of this kind are installed in traffic areas. The material with which these traffic areas are coated—preferably bituminous materials—is customarily applied while in a heated condition. The temperature of the coating to be applied to the traffic area in this case is approximately 150-170° C. To prevent the materials, which are usually viscous fluids at this stage, from flowing into the hollow bodies, for example drainage devices, that have been embedded in the unfinished traffic area, their cover arrangements are installed before the coating layer is applied to the traffic area. As a result, the during application the hot material comes into direct contact with the cover, and in some cases flows over its entire surface. Then it is only after cooling that the cover can be exposed again. Because the coating material is so hot, during the application procedure there is severe heating of the cover and, of course, of the attached locking elements as well. The locking elements made of plastic as described above are especially vulnerable to severe damage by this heating.

Thus because the present locking element is not in direct contact over its entire surface with the underside of the cover, and moreover an air gap is formed between the underside of the cover and the locking element, if a high temperature should be imposed on the cover the locking element will not be excessively heated. This improves its durability. The protective effect of course not only operates when a temperature increase associated with application of a heated surface-coating material occurs, but is significant even with respect to warming of the initially cited covers as a result of direct solar irradiation. A very effective distance between the underside of the cover and the locking element has been found to be a distance of substantially 0.4 to 0.8 cm.

Preferably the air gap between the underside of the cover and the locking element is formed so as to permit circulation between the ambient air and the air in the air gap. The exchange of air in the air gap provides an additional degree of cooling, which counteracts heating of the locking element, thus increasing its durability and improving its usability.

To enhance the insulation, an additional thermally insulating element is preferably provided between the underside of the cover and the locking element. This thermal-insulation element can be loosely inserted into the air gap, but can also have been previously disposed on the underside of the cover or on the locking element itself. Here it is conceivable to use any of the insulating materials known in the state of the art.

Preferably the locking element is disposed within a receptacle in the cover so as to be slidable between a removal position and a fixation position. The removal position is used for removing the locking element or exchanging it for another locking element, for instance when there is a defect; in the fixation position, the locking element is securely fixed to the cover. This makes it possible, among other things, for a supplementary thermal-insulation element to be easily inserted into the air gap. Furthermore, such a design of course ensures that the required distance between locking element and underside of the cover is maintained.

Thermal insulation of the locking element with respect to the underside of the cover is naturally especially advantageous in the case of locking elements made of plastic, in particular thermoplastic plastics, as has already been mentioned above. Here it is conceivable not only to dispose an air gap between locking element and underside of the cover, but rather in general to take care that the holder attaching the locking element to the cover has the lowest possible thermal conductivity, and/or is so constructed that the transmission of heat is as slight as possible. This is enabled by, among other things, a minimization of the cross sections of the holder.

Additional embodiments of the invention will be apparent from the subordinate claims.

In the following the invention is described with reference to an exemplary embodiment, which is explained in greater detail with reference to the drawings, wherein

FIG. 1 is an isometric, sectioned representation of a cover arrangement in a first exemplary embodiment, and

FIG. 2 shows the exemplary embodiment of FIG. 1 in section, in the installed state and after a coating has been applied to a traffic area.

In the following description, the same reference numerals are used for identical parts or parts with identical actions.

FIG. 1 shows a cover arrangement 1 for a surface drainage device, consisting of a frame 20 and a cover 10 set into said frame. The cover 10 is seated on seating regions 22; 22′, which are formed in the frame 20. So as to lock the cover 10 against the frame 20, the cover comprises two locking elements 11; 11′, which are disposed on an undersurface 19 of the cover 10. It is of course also possible to attach more than two locking elements 11; 11′ to the cover 10, in order to enhance the locking capability.

Because the locking elements 11; 11′ are identical, as are their means of attachment to the cover 10, here only the locking element 11 with its associated attachment to the cover 10 will be explained in greater detail, to serve as an example for all the additional locking elements 11; 11′ that might possibly be provided.

The locking element 11 is engaged with a receptacle 12 that is integrally disposed on the cover 10. For this engagement, the locking element 11 comprises on each side a guide groove 15, into which is inserted a guide lug 14 formed on each side of the receptacle 12. This construction enables the locking element 11 to be pushed into the receptacle 12, i.e. to be shifted between a removal position and a fixation position.

The receptacle 12 and locking element 11 are constructed so that when the locking element 11 has been pushed into place, an air gap 30 is formed. For this purpose the locking element 11 is separated from the underside 19 of the cover 10 by a distance d. This air gap 30 is so formed that it makes possible circulation of air along the path L_(Z), between the air gap 30 and the ambient air. Hence this assists the thermal insulation of the locking element 11. In addition, to improve the insulating performance, a thermal-insulation element 19 is formed on the locking element 11. It would furthermore be possible to increase the resistance to heat transfer between cover 10 and locking element 11 by reducing the cross-sectional areas of the receptacle 12.

In FIG. 2 the cover arrangement 1 previously described is shown in the installed state, in section and shortly after the coating 2 has been applied to the traffic area. The cover arrangement 1, consisting of frame 20 and cover 10, is here disposed on a shaft structure 3. This shaft structure 3 can be, for example, an inspection chamber or also a collecting shaft for the removal of water. The substrate adjacent to the shaft structure 3 here consists of the coating 2 for the traffic area, an underlying carrier layer 4, and the ground 6 on which these constructions are based. The traffic-area coating 2 has preferably been applied to the carrier layer 4 while in a heated state, after the cover arrangement 1 has already been installed. After the traffic-area coating 2 has been rolled in, any excess coating material 7 above the cover 1 is punched out at the edge regions 5 and removed. The cover 1 is lifted to the level of the coating surface. After the covering material 7 has been cut out, access to the cover 1 and the shaft structure 3 is again ensured. Because customarily the traffic-area coating 2 is applied while in the heated state (ca. 170° C.), the cover 1 is also severely heated. In accordance with the invention, therefore, the cover 1 comprises the air gap 30, which serves for thermal insulation of the locking element 11; 11′. This ensures that the locking element 11; 11′ will not be damaged by heating of the cover 10.

At this juncture it should be pointed out that all of the parts described above are claimed as essential to the invention, individually or in any combination, in particular the details shown in the drawings. Modifications thereof are familiar to a person skilled in the art.

LIST OF REFERENCE NUMERALS

1 Cover arrangement

2 Coating for traffic area

3 Shaft structure

4 Carrier layer

5 Edge region

6 Ground

7 Coating material above cover

10 Cover

11, 11′ Locking element

12, 12′ Receptacle

14 Guide lug

15 Guide groove

16 Thermal-insulation element

17 Upper surface

19 Underside

20 Frame

22, 22′ Seating region

30 Air gap

d Distance

L_(Z) Air circulation path 

1. Cover for a hollow body that is to be embedded in the ground and to be opened, comprising an upper surface over which pedestrian or vehicular traffic can pass, an underside; and at least one locking element that is attached to said underside such that the upper side is closed over the locking element and that is disposed at a determined distance from the underside in such a way as to form an air gap for thermal insulation between said underside and said locking element.
 2. Cover according to claim 1, wherein said predetermined distance is between 0.4 cm and 0.8 cm inclusive.
 3. Cover according to claim 1, wherein said air gap is constructed so that an air circulation is possible between ambient air and air in said air gap.
 4. Cover according to, claim 1, wherein a supplementary thermal-insulation element is present between said underside and said locking element.
 5. Cover according to, claim 1, wherein said locking element is made of a plastics material.
 6. Cover according to claim 1, wherein said locking element is moveable within a receptacle formed by the cover, between a removal position and a fixation position.
 7. Cover according to claim 1, wherein said locking element is made of a thermoplastics material. 